Improvement in fire-proof safes



lamps in eud among the plaster. This is 0011- and perm enemy of set. 4

UNITED STATES WALTER. MARVIN,

* WW -FWT JTEiD hiiiliiQiisiiE Qt??? PATENT OFFICE.

on new YORK, N. Y

IMPROVEMENT ilN Fl RE-eRooF SAF-E S, etc;

l Specification formingpart of Letters PatentvNo. 41,521, dated February 9, 1864.

To aZ'Z ug'hom it mayrconcemr fBe it knownthat I, WALTER MARVIN, of New-York, in the county'and State of New York, have invented a new and useful 1m.- prove'ment inFilli n g for Fire-Proof Safes and; vI.hereby'de'clare that the following is a toll, cleari.'and.exact description of the same.

--' 'IIlfhis-invention relates to the production of va fire-proof filling forsafe's. which is designed zto-obviate; some of the objections stillentertaiued'again'st those heretofore'in' use. I have.

recently obtained Letters Patent of the United State's'for the use, of calcined or, dry. plaster- -ot-paris::so combinedwith alumesthat' the" changes efi'eeted by; time and-,fire produce a 'I'cellular filling which is perfectly dry, fire" proof, and without corros-iveaction on the iron, while it possesses the requisiteilightness The present invention "is fan improvement upon the invention last referred to, the object being the lessening of the cost in material and labor; and I have accomplishedthis in the manner as follows: I ,firstproduceballs or lumps of aluin'coated with calcined plaster; Tot-his efiect 'I use a large platform or tray suspended by means of ropes or chains tied to a ring,commonto all, in a-hook fast in the ceiling or other elevated point in the room in which-the operation isto take place."This tray is provided with handles, so that the at-.

tendant can impart to-ita swinging motion'in 'any direction desirable-i. 0.,back and forth,

'l.aterally 'and tipping, or any other movement of which the suspension-hook is the center of motion. Into this tray 1 placeiumps of alum varying in size and weight from onegrainto a half-ounce. Thewholc is then gently steamed by conducting a small steam-pipe over the surface of the lumps .of alum, or by sprinkling 1 water vwith an ordinary watering-pot, the 1102 zleoif which emits very fine streams of water over thealum until the surfaces of the lumps become suifieiently damp to cause calcined plasterof-paris powdered to adhere to them. I then throw the powdered'plastcr upon the lumps and then swing'the tray to agitate .the

tinned-amt mach lump ct alum is coated with ifl hh itil ethane whic i c m ng Tin. c n ac w'iththe moistsurface'bfthe alum becomes set. When tne first coating has been thus formed the same-operation is. repeated until the-required thickness of shell or envelopeds attainedt; e., froin one-eighth of an inch; ,upward,'according tothe size of the lumps coated, a small piece not requiring-as thick a ieoating as larger pieces. This operation of coating the lumps with plasteris verysimilar to that employed by manufacturers of sugarcandy in coating the pits of almondswith sugar; and Lhave found that a gentle or. low heat will facilitate or'hasten the process, par-.

ticularly so'in' damp weather. This constitutes the first step of the process. "L'ne'xt'take clay andealcineit sufficiently to driveottlthe water'it 'contains',.and then grind or pulverize thesame. This constitutesthe seoondstep." Ithen intersperse the. pieces of alumn. held within their plastercells, prepared in the manner I- have described, throughout the'calcinedclay and fill 'mysafes' withthis compound; and this constitutes the third and last'step of my improved mode of; 1 fi lling safes." The result of these operations is that aperfectly drysafe-lining is obtained, which, when subjected, by accident orotherwise, tot'he'action of 'fireis not liable to shrink, asis the ease in'all -alnm and clay safes heretofore in use. This effect is due to the strength and porosity-of: the coating of the alum, which,',whe'-. the alum is fused, permits-the vapor and steam to pass out into the clay and act as 'areducer-ot' heat,

and at the same time preserves the cellular structure of the whole iii-ling. In this way clay may be-substitutedfor the-great bulk of plaster-of-paris used in my patented process hcreiubefore referred to, and the consequence is that quite as good a safe may be madeat a less cost of material andla'bor, I

Having thus fully described my invention and the manner in which the same is or may be carried into etfect, I claimt 1. As a new composition of matter for the fire-proof lining or filling ot' safes and other like fire-proof structures, alum, gypsum, and clay combined in'the manner hereinbet'ore set forth. v

2. The coatingof liiinpsof alum with cal-'- ci'ned and powdered-gypsum, as described, in

-s. kw HMFL- combination, with incorporating such coated lumps in dry or calcined clay, substantially in the manner and for the purposes set forth.

3. 1 As a new article of manufacture, safes or other fire-proof structures the filling of which is composed of alum, gypsum, and clay, under a the arrangement or combination hereinbefore set forth.

in testimony whereofl have signed my name to this specification before three subscribin witnesses.

WALTER K. MARVIN. Witnesses:

I. DAVENPORT, JAMES GREEN, EDWARD BISSELL. 

